Antimalarial activity of extract and norbergenin derivatives from the stem bark of Diospyros sanza‐minika A. Chevalier (Ebenaceae)

Abstract

The methanol extract from the stem bark of Diospyros sanza-minika as well as five norbergenin derivatives isolated from this crude extract were evaluated for their in vitro activity against Plasmodium falciparum K1 and cytotoxicity on MRC-5 cells. 4-O-(3'-methylgalloyl)norbergenin was found to be the most potent compound (IC(50) 0.6 μg/mL; CC(50) 24.7 μg/mL), followed by 4-O-galloylnorbergenin (IC(50) 3.9 μg/mL; CC(50) > 64 μg/mL) and 11-O-p-hydroxy-benzoyl-norbergenin (IC(50) 4.9 μg/mL; CC(50) > 64 μg/mL). Norbergenin and 4-O-syringoylnorbergenin were inactive (IC(50) > 32 μg/mL; CC(50) > 64 μg/mL). The antimalarial activity of the pure constituents and of the methanol extract from the stem bark of Diospyros sanza-minika is reported for the first time. The results provide interesting baseline information for the potential use of the crude extract well as some of the isolated compounds in the search for novel antimalarial compounds.

Antimalarial activities of medicinal plants traditionally used in the villages of Dharmapuri regions of South India

“…Kantamreddi and Wright (2008) reported four Indian Diospyros species viz., Diospyros melanoxylon, Diospyros peregrine, Diospyros sylvatica, and Diospyros tomentosa in which methanolic extracts were found to have significant activity (IC 50 = 16.5-92.9 g/mL), against chloroquine-sensitive 3D7 strain of Plasmodium falciparum and similar activities against chloroquine-resistant K1 strains (IC 50 = 20.5-121.6 g/mL). The compound 4-O-(3 -methylgalloyl) norbergenin isolated from the stem bark of Diospyros sanza-minika was highly active against Plasmodium falciparum (IC 50 = 0.6 g/mL), whereas 4-O-galloylnorbergenin (IC 50 = 3.9 g/mL), 11-O-phydroxy-benzoyl-norbergenin (IC 50 = 4.9 g/mL) and norbergenin and 4-O-syringoylnorbergenin (IC 50 ≥ 32 g/mL) were less active (Tangmouo et al, 2010).…”

Antiplasmodial natural products: an update

“…Likewise, a galloylated norbegenin derivative, 4- O -(3′-methylgalloyl)norbergenin ( 341 ), was obtained as the most active antiplasmodial constituent of Diospyros sanza - minika (Ebenaceae) stem bark extract. Norbegenin, which was also isolated from the same extract, was 32 times less active (40.15 µM), indicating that the additional galloyl group is beneficial to the antiplasmodial activity [213]. Antiplasmodial activity was demonstrated for Anogeissus leiocarpus (Combretaceae) methanol bark extract (IC 50 = 18.8 µg/mL), and ellagic acid ( 342 ) was isolated as the most active antiplasmodial metabolite of the extract against 3D7 P. falciparum [214].…”

Antiplasmodial Natural Products

“…Norbergenin derivatives 249-251 ( Figure 29 ) isolated from the stem bark of Diospyros sanza-minika (Ebenaceae) were evaluated for their in vitro activity against the P. falciparum K1 and cytotoxicity toward MRC-5 cells ( 249 : IC 50 8.4 μM; CC 50 > 137.4 μM, 251 : IC 50 11.3 μM; CC 50 > 147.5 μM, 250 : IC 50 1.3 μM; CC 50 51.5 μM). Compound 251 possesses an O - p -hydroxybenzoyl group at C-11, while 249 and 250 have O -galloyl, and O -(3′-methylgalloyl) groups, respectively, at C-4, which may play an important role in their antimalarial activity [ 89 ].…”